(a) Field of the Invention
The present invention relates to a photoresist composition, a method for forming a film pattern using the same, and a method for manufacturing a thin film transistor array panel using the same.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of commonly used flat panel- displays. An LCD includes two panels having a pixel electrode and a common electrode respectively, and a liquid crystal layer interposed between these panels. Generally, the pixel electrodes are disposed on one of the panels and arranged in a matrix shape. The common electrode is disposed on the other of the panels and covers substantially the entire surface thereof. A pixel electrode and the common electrode are supplied with a data voltage and a common voltage, respectively, to generate an electric field in the liquid crystal layer. The electric field changes the orientations of liquid crystal molecules, which in turn changes transmittance of incident light to display an image.
In order to apply respective voltages to the pixel electrodes, switching elements such as thin film transistors (TFTs) having three terminals are separately connected to the pixel electrodes. The panel having the pixel electrodes and TFTs (referred to as “TFT array panel” hereinafter) includes a plurality of gate lines transmitting control signals for the TFTs and a plurality of data lines transmitting data voltages. Each of the TFTs transmits or blocks data signals for a pixel electrode from a data line in response to a scanning signal from a gate line. The switching elements such as TFTs are also included in active matrix organic light emitting diode displays (OLEDs). The TFT separately controls each light emitting diode.
The TFT array panel includes a plurality of thin films such as a gate layer, a data layer, and a semiconductor layer. The thin films are respectively patterned by photolithography processes using separate photo masks. However, when an additional mask is added, various process steps such as light-exposure, development, and etching are required, and accordingly manufacturing time and cost significantly increase. Therefore, it is preferable to decrease the number of masks required during processing.
To pattern the data layer and the semiconductor layer, it has been suggested to use one photo mask having a slit pattern, in which a channel portion of a TFT is formed between a source electrode and a drain electrode of the TFT using the slit pattern of the photo mask. However, using such a method, photoresist remaining in the channel portion may be non-uniform, and therefore the semiconductor layer in the channel portion may be non-uniformly etched. Further, the data layer can be over-etched, causing the semiconductor layer under the data layer to be broadly exposed near the edges thereof. The exposed portions of the semiconductor layer unnecessarily reduce the aperture ratio of an LCD.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.